Summary:
The extension was a quick hack from me to make it easier to locate non-core
code when doing extension development. It seems a good idea to add colors in
general so it's named "morecolors" with the hope that we can colorize more
places in the future.
Test Plan: Added a test
Reviewers: #mercurial, durham
Reviewed By: durham
Subscribers: durham, mjpieters
Differential Revision: https://phabricator.intern.facebook.com/D4884999
Signature: t1:4884999:1492473666:89a6756b231eac4274fa05d489480229146bdab8
